CMake: document intention to run more tests on modules

- Loading the module will check Python modules for syntax,
   and C++ modules for symbols. This would be a good idea,
   except for where it calls exec() and does things to the
   running system. Most modules are harmless with an empty
   config, but you never know (e.g. a process module).

CMakeModules/CalamaresAddModuleSubdirectory.cmake

@@ -148,4 +148,16 @@ function( calamares_add_module_subdirectory )
             math( EXPR _count "${_count} + 1" )
         endforeach()
     endif()
+
+    # Check that the module can be loaded. Since this calls exec(), the module
+    # may try to do things to the running system. Needs work to make that a
+    # safe thing to do.
+    #
+    # if ( BUILD_TESTING )
+    #     add_test(
+    #         NAME load-${SUBDIRECTORY}
+    #         COMMAND loadmodule ${SUBDIRECTORY}
+    #         WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+    #         )
+    # endif()
 endfunction()